Apple Puffed Pancake

Yesterday we went apple picking, so this morning we had this! It was devoured immediately.
Apple Puffed Pancake
6 eggs
1 1/2 cups milk
1 cup flour (all-purpose)
3 T granulated sugar
1 tsp vanilla extract
1/2 tsp salt
1/2 tsp cinnamon
1/4 cup butter
2 apples, peeled and thinly sliced
2-3 T brown sugar
Preheat oven to 425°F. In a blender, mix eggs, milk, flour, granulated sugar, vanilla, salt and cinnamon. Pulse briefly to blend. If you have one fluted porcelain quiche dish that's 12 inches across, you can use that. If you don't, you can use two that are 9 inches across, or you can use a 9x13 baking dish.
Place the butter in your pan(s) and put it in the oven to melt the butter. When the butter is melted, add the apple slices to the butter and return the dish to the oven. When the butter starts to sizzle (in a couple of minutes), remove the pan and pour the batter over the top of the apples. Sprinkle with brown sugar. Return the pan to the oven and bake for 20 minutes.
Your pancake will get puffy while it's baking but will fall slightly after you pull it from the oven. Serve immediately. Serves 6 (if some of them are children).